Effects of administration of ergotamine tartrate on fertility of yearling beef bulls

GM Schuenemann
Jl Edwards
MD Davis
HE Blackmon
FN Scenna
Barton Rohrbach, University of Tennessee - Knoxville
AM Saxton
Henry S. Adair, III, University of Tennessee, Knoxville
FM Hopkins
JC Waller
FN Schrick

Abstract

Sixteen yearling bulls were utilized to investigate administration of ergotamine tartrate on semen parameters, fertilization, and endocrinology. Bulls were allotted to a control diet of cracked corn, corn silage, and soybean meal (CON, n = 8) or a diet supplemented daily with 40 microg/kg body weight of ergotamine tartrate (ET, n = 8). Blood samples, average daily gain, scrotal circumference and rectal temperatures were collected every 14 day. Semen samples were obtained every 60 day and evaluated for motility and morphology. Scrotal temperatures were obtained by thermography immediately before electroejaculation. Semen from a subset of bulls from each treatment was also evaluated for in vitro fertilization. Administration of ET increased rectal temperature and resulted in lower scrotal temperatures compared to CON bulls (P < 0.05). However, prolactin, scrotal circumference, testosterone, and semen motility and morphology did not differ between groups throughout the experimental period (224 day). Cleavage rates of embryos derived from in vitro fertilization (IVF) with semen of bulls, fed with ET, were reduced compared to CON (P < 0.05); however, development of cleaved embryos to blastocyst did not differ between treatments. In conclusion, extended exposure of bulls to ET appeared to reduce fertilization potential of sperm.